Telemetering



Aug. 3, 1948. H. J. LOVEGROVE TELEMETERING 2 Sheets-Sheet 1 Filed Nov. 6, 1943 lllll INVENTOR. Ja'sepk L avg/vie Aug. 3, 1948. H. J. LOVEGROVE TELBMETERING 2 Sheets-Sheet 2 Filed Nov. 6, 1943 iil llillllilih IN V EN TOR.

He/Y Josepk A away/(we BY fl' Mrm Patented Aug. 3, 1948 dinett ileld, Ill, a corporation Company, satin:- Illinois Ninmbex 6, 1., Serial No. 509,179 ll GM October 24. 1942 The present invention concerns improvements in or relating to remote indication of measurements. In a known system of remote indication a transmitter comprising a three-phase two-pole stator and a single-phase two-pole rotor is empioyed; being connected over a plurality of leads with an indicator oi similar construction, the single-phsse'two-pole rotors being supplied from a-common source oi alternating current. while the currents induced inthe stator coils of the transmitter'are fed to the corresponding coils oi. the indicator. The arrangement is such that ii the rotor of the transmitter is set to the position corresponding to the measurements to be indicated then diil'erent currents will be induced inthe respective coils of the stator dependent on the position of the rotor, and such currents ilowing through the stator coils of the indicator in-' teract with the field generated by the rotor to cause the rotor to take up a position corresponding to the position taken up by the rotor of the transmitter and'therefore corresponding to the measurement to be indicated.

- Such a, construction involves a somewhat heavy moving system, the employment of'substantial hearings to carry such a system, and the use of slip rings, and generally is not suitable for aircraft wherein heavy vibration is experienced. Certain attempts have been made to adapt the above known system for use in aircraft but the instruments evolved are heavy and not too robust. This system of remote indication has however, several advantages, chief among which are that I Claims. (CL 81H) to each other, to cause currents to be generated in said other coils in proportionate values, which characterise the position. Each current so generated in each of said other coils is led to a corresponding coil in a receiver whereby an armature thereat is caused to take up a position corresponding to the first-mentioned armature.

According to a further feature of the invention a transmitter comprises an exciting coil, a plurality ofother coils fixed with relation to the exciting coil and arranged to be linked magnetically with said exciting coil to a variable extent one basic panel instrument only is necessary for measuring diflerent quantities such as; engine speed. engine temperature. air temperature. oil temperature, oil pressure, exhaust temperature. exhaust pressure, fuel level, and many others. all that is necessary is to, have the scale plate calibrated in suitable Moreover, the instrument can be made with a scale angle of nearly 360 and the whole system is practically independent of temperature errors. ,7

The object of the present invention is to provide a remote indicating system having the aforeby a rotatable armature, whereby it said exciting coil is fed with alternating current, current is induced into said other coils in proportions dependent upon the-position ,oi the armature.

According to a further feature of the invention a receiver is provided comprising an exciting coil. a pluraiityof other coils fixed with relation to the exciting coil, and a rotatable armature ar-' ranged to be set to ditierent angular'positions in accordance with the values of the currents ilowing in said other coils. Preferably a transmitter and receiver are identical in construction except that in the case of a transmitter the armature is set in accordance with the readings of the transmitter' while in the case or a receiver the armature takes up a position dependent upon the proportionate values of the currents received.

= The invention will be better understood by reierring to the accompanying drawings. in which Fig. 1 shows diagrammatically a. fragmentary axial sectional view of one construction of instrument which may be either a transmitter or receiver. I

' Fig. 2' shows an end view oi Fig. 1, employing one shape or armature.

Fig. 3 shows an end view of Fig. 1, employing an alternative shapeo'i armature.

' Fig. 4 shows the circuit connections between a transmitter and a receiver.

Fig. 5 shows in end elevation an alternative construction to that illustrated in Fig. 1.

Fig. 6 is a diagrammatic side or axial view showing a further alternative construction.

Fig. 7 is an axial sectional view of a construction similar to that shown in Fig. 5, with a magnetic arrangement for ensuring that the'pointer is 01! scale when no current is flowing.

Figs. 8 and -9 show a further alternative of robust construction.

Referring to Fig. 1, X represents the operating coil which is excited from an alternating current supply irrespective 01' whether the device is functioning as a transmitter or receiver. A. B and C The yoke YA is located with its base between coils A and B, the yoke YB between coils B and C, and the yoke YC Just beyond C. The axial lengths or depths of the yokes are diiferent'so that they all terminate in substantially the same plane normal to the staif S. as shown at the left of Fig. 1. The radius of each yoke is enlarged so as to leave a gap between the outer periphery of coil X and each yoke so as to provide a path for the operating iron I. The staff S passes through the tube TM and is supported on jewelled or like bearings JB at each end. At one end the stat! carries a pointer P and the operating ironI, while at the other end it carries a damping cup D.

The pointer P moves over a scale to indicate the position of the armature or inductor rotor I. This armature or inductor rotor may be either sector shaped with a curved rim extending into the circular space left between the operating coil X and the yoke extensions YA, YB, YC as shown in Fig. 2, or it may be heart shaped as shown in Fig. 3. In the lattercase it is only necessary for the yoke extensions to extend slightly beyond the left hand side for operating coil X and there is no necessity of leaving a recess or gap between the yoke extensions and the coil X, as in Fig, 2.

The damping cup, which is preferably made of aluminiumJsso arranged that its side extends into an air gap between a permanent magnet M and a magnetic ring it forming a return path for the damping flux. An adjustable counterbalance,

diagrammatically indicated at F, counterbalances more or less of the. off-center weight of the inductor rotor I.

The circuit connections between the transmit-- ter and receiver, which are identical in construction, may conveniently be as shown in Fig. 4. The reference letters X, A, B, 0 represent the coils for the transmitter as described with reference to Fig. l, and the reference letters Xi, Al, Bl, cl represent like coils for the receiver. .It will be noted that a source of A. C. supply is led to the coils X and XI in parallel or in series. with this arrangement only three synchronizing conductors through paths the reluctance of which depends upon said angular relationship for each coil. In the position shown the coil A will be very tightly linked while the coils B and C will be very loosely linked so that there is a larger current induced in A and very little in B and C. These currents travel over the connecting leads to coils Al, BI and Cl respectively and consequently the operating iron of the receiver moves to a position where the strongest field is created and this corresponds exactly to the position of the pointer P at the transmitter so that the pointer at the receiver reads the same. Y

If for instance the pointer P at the transmitter was "set toa position at 90 in a clockwise direction (as viewed in Fig. 2) to that first considered,

in addition to there being a linking between coils X and A there will also be a tighter linking between coils X and B. Hence currents will be induced in coils A and B proportional to the relative field strengths. These currents in the same proportions excite coils Al and BI at the receiver and the operating iron of the receiver moves to a position where the strongest field is created which will be when the combined eifect of coils Al and BI is such that the operating iron is influenced by the magnetic fields created thereby in the same proportions as the exciting currents. Therefore the operating iron and the pointer will take up exactly the same position at the receiver as represented by the pointer P at the transmitter.

Fig. 5 shows an alternative construction in which the coil X is mounted on a trian ular magnetic plate MP and is surrounded by' the three coils A, B and C, which are also mounted at the three corners of the triangular plate so as to be V angularly separated with respect to the axis of the coil X at angles of 120. The coil X has a magnetic tubular core which is connected to the magnetic plate MP and through which a stafl 8 passes carrying a pointer P and an operating iron I. On. each core of the coils A, B and C are mounted yoke members YA, YB, YC respectively shaped as shown, that is to say. with a sector portion connected to the core and an upturned portion having itsedge curved so as to be coaxial with the stai! S. The operating iron I is shaped with a boss on the stat! S and an arm carrying plugs and lacks which may be used, although it v will be \mderstood that if desired separate leads may be provided for some or all of the coils, in

which case the number of interconnecting leads would be increased.

The operation is as follows:

At the transmitting end the pointer P is set to a position on the scale corresponding to the read.- ingto be transmitted; Theoperatlng iron therefore takes up a position which is differently disposed as regards its angular relationship with respect to the three yokes YA, YB, YC. Hence thecoilXwillbelinkedwiththecoilsmBandC at its end a plate curved with its centre on the axis of the stall, this curved plate being adapted to travel between the coil X and the yokes YA. Y8 and Y0. It will thus be clear that according to the position of the pointer P and the operating iron I, currents will be induced in the coils A. B and C in proportion to the extent that the operating iron enters the resp ctive fields. The circuit connections and operation are substantially as previously described.

Fig. 6 shows a further alternative in which a cup shaped yoke member Y is provided 0! magnetic material having a central core for the operating coil X'- and radial cores disposed at 120' to each other and projecting radially inwardly from the inner side of the cup. these three cores being for the coils A, B and C respectively. The operating iron I is supported on a stall 8 near the vicinity of the core for the coil X and having an arcuate portion adapted to travel in a circular path just clear 0! the inner ends of the cores of coils A, B and C. The iron I has-an arcuate length or span of approximately as in Pig. 2, and here again it is not felt that any further description is necessary.

Pig. 7 shows an arrangement corresponding to that shown in Pig. but in which the bearing arrangement is illustrated in greater detail and in which the coil x is not mounted directlyagainst a supporting plate. In this figure it will be noted that the coils A, B and C, or which only A and B are shown, are arranged at three corners of a magnetic plate '1'? conveniently of the shape of an equilateral triangle and having a central hole. Magnetic cores MC extend from this plate at right angles thereto for each of the coils A, B and C while a tubular magnetic core TC extends from the central hole for the coil X. This tubular member is threaded to enable thestair S to be supported in two bearings. One bearing consists or a screw tube 8T which is threaded into the tubularmagnetic core TC and provides a bearing for the staff at one end. while inside there is a space in which a spring SP is compressed against a plate which acts against an end of the staff, the strength of which spring can be adjusted by means of a screw SC.

An iron ring IR is screwed on to the end of the magnetic tubular member farthest from the triangular plate 1?, and a bearing is secured by screws to this iron ring, which bearingis in the form of a bushing and extends into themagnetic tube TC. The end or this extension is given a camlike'shape CM for a purpose to be described later. The stair 8 carries an operating iron I which is conveniently sector shaped with an upturned rim curved so as to travel round the outside oi the coil X. The staff also carries a pointer P which rotates in front of a scale SL secured by pillars to the cores MC. Each core is provided with a yoke member such as YA, YB which are secured to the end of the cores MC and serve to act as pole pieces for the coils A, B and C similar to those previously described. It will be noted thatthe stall is adapted to move'in this bearing in a longitudinal direction.

As illustrated it is assumed that operating current is flowing through the coil X, consequently the operating iron is attracted to the position shown where the stall S compresses the spring 8? and the location pin LP is held awa from the cam CM. On the removal of operating current, the spring SP becomes eflective to move the stall to the left, consequently the location pin LP engages the cam surface CM and the staff is caused to rotate to bring the pointer to an oilscale position. The advanta e of this method of bearing construction is that no undesirable control force is placed on the Pointer under opera ingconditions.

In the arrangement illustrated in Figs, 8 and 9 the stator is formed' of laminations ll of ring shape with inwardly facing teeth I l forming slots in which the stator coil may be wound as in the well known construction oi three-phase machines illustrated diagrammatically in Fig. 8, while the rotor consists of two 'sectionally shaped irons I extending in diametrically opposite directions of two units adapted to operate as a transmitter and mounted on opposite ends of the staff S. In 4 the space between the irons the stationary exciting coil x is mounted. The exciting coil-is wound on a tubular member TM of magnetic material through which the stafl carrying the irons passes. Two cup shaped members CSM form a casing which are secured together by bolts or the like (not shown) and serve to secure the laminations II in position. These cup shaped members which are formed of non-magnetic material are provided one with an end bearing i2 and the other with a bearing it through which the stafl passes. The. stall carries the pointer P in front of the scale sw secured to the latter cup-shaped memher. The coil X is secured in position with respect to the laminations II and the stall? and irons are subsequently placed in position.

I claim: i

i. In telemetering apparatus, the combination of two units adapted to operate as a transmitter and a receiver in a telemetering system, each of said units comprising a fixed exciting coil and a plurality of fixed synchronizing coils arranged in cooperative relation, said plurality of fixed synchronizing coils being all wound concentrically about a common axis, means for energizing the exciting coil of each unit with a periodically varying current, an inductor armature of magnetic material at each unit for establishing variable magnetic paths between the exciting coil and the synchronizing coils of its respective unit, and circuit connections between the synchronizing coils of one unit and the synchronizing coils .of the other unit.

2. In telemetering apparatus, the combination of a plurality of units adapted to operate as a transmitter and a receiver in a telemetering system, each of said units comprising an exciting coil and a plurality of synchronizing coils all wound concentrically about a common axis and held against movement relatively to each other, means for energizing the exciting coil of each unit with an alternating current, an inductor armature at each unit operative by rotation to establish variable magnetic paths between the exciting coil and the synchronizing coils of its respective unit, and circuit connections between the synchronizing coils of the respective units.

3. In telemetering apparatus, the combination and areceiver in a telemetering system, each of said units comprising a stationary exciting coil, means for energizing the exciting coil of each unit with an alternating current, an inductor armature of magnetic material rotative coaxially of said exciting coil at each unit, a plurality of stationary synchronizing coils all wound concentrically about the common axis of said exciting coil and said inductor armature whereby rotation of said armature is operative to establish variable magnetic paths between the exciting coil and the synchronizing coils, and circuits connecting the synchronizing coils of one unit with the synchronizing coils of the other unit.

4. In telemetering apparatus, the combination of two units adapted to operate as a transmitter and as a receiver in a telemetering system, each of said units comprising a stationary exciting coil and a plurality of stationary synchronizing coils having their magnetic axes concentric to the magnetic axis of said exciting coil, means for energizing the exciting coil of each unit with an alternating current, magnetic pole members extending from each of said synchronizing coils and grouped in circular relation to said exciting coil, an inductor armature of magnetic material at each unit for establishing variable magnetic paths between the exciting coil and the magnetic pole members of said synchronizing coils, and circuits connecting the synchronizing coils of one unit with the synchronizing coils'of the other unit.

5. In telemetering apparatus, the combination of two units adapted to operate as a transmitter and as a receiver in a telemetering system, each of said units comprising an exciting coil and a plurality of synchronizing coils stationarily mounted in coaxial relation, means forener- 1 gising the exciting coil or each unit with a period- -icaiiy varying current, an inductor armature or magnetic material at each unit for establishin variable magnetic paths between the exciting coil and the synchronizing coils of its respective unit, and circuit connections between the synchronizing coils of one unit and the synchronizing coils o! the other unit.

. 6. In telemetering apparatus. the combination of a fixed exciting coil, a plurality of fixed synchronizing coils disposed coaxially of said exciting coil, means for energizing the exciting coil with a periodically varying current, and a rotary inductor armature of magnetic material ior establishing variable magnetic paths between the exciting coil and the synchronizing coils.

7. In telemetering apparatus, the combination ot a stationary exciting coil and aplurality of stationary synchronizing coils arranged in coaxial relation, means for energizing said exciting coil with an alternating current, and an inductor armature of magnetic material for establishing variable magnetic paths between the exciting coil and said synchronizing coils.

8. In a telemetering system the combination of a transmitter and a receiver each having a stationary exciting coil and a plurality of telemetercoils of the transmitter and the telemetering coils of the receiver whereby variations in the flux density threading the transmitter telemetering coils causes substantially proportionate variations in the energization of the receiver telemetering coils, and a receiver inductor rotor at said receiver rotatable to diflerent positions in response to such variations in the'energisation of the receiver telemetering coils.

9. In a telemeiering system, the combination of a transmitting unit and a receiving unit, each of said units comprising a stationary exciting coil and at'least three stationary synchronising coils all arranged in axial alignment-a spindle extendingaxially through said coils. a rotary damping sy'stemconnected-to one end of said spindle, a segment shaped inductor rotor to the other end 0! said spindle, segment shaped stator -members extending i'romeach of said synchrosnizing coils for coasting with said inductor rotor, means for supplying alternating current to the exciting coils of both units, and parallel circuits connectingthe synchronizing coils otboth units.

HENRY JOSEPH LOVEGROVE,

' REFERENCES CITED- I The following references are of 'record, in the tile oi thispatent:

UNITED STATES PATENTS Number Name Date 705,482 Thiermann July 22, 1902 1,431,627 Bristol et a1 Oct. 10, 1922 1,653,947 Decker Dec. 27, 1927 1,706,149 Ellis Mar. 19, 1929 FOREIGN PATENTS Number Country Date 155,848 Great Britain Dee, 1920 

